Convertible aircraft



Jan. 28, 1964 E. F. ANDREWS 3,119,577

CONVERTIBLE AIRCRAFT Original Filed Jan. 27, 1953 9 Sheets-Sheet 1 Jan.28, 1964 E. F. ANDREWS CONVERTIBLE AIRCRAFT 9 Sheets-Sheet 2 OriginalFiled Jan. 2'7, 1953 i flfeyv ewz r' low/n2 .da/reua @Waeg I Jan. 28,1964 F. ANDREWS 3,119,577

CONVERTIBLE AIRCRAFT Original Fil'ed Jan. 27, 1953 9 Sheets-Sheet 3 ui HFLIGHT gmac'nou A T TRANSIHQN affvz weg Jan. 28, 1964 E. F. ANDREWS3,119,577

CONVERTIBLE AIRCRAFT Original Filed Jan. 27, 1953 9 Sheets-Sheet 5 E. F.ANDREWS CONVERTIBLE AIRCRAFT Jan. 28, 1964 9 Sheets-Sheet 6 OriginalFiled Jan. 27, 1955 Jan. 28, 1964 E. F. ANDREWS 3,119,577

CONVERTIBLE AIRCRAFT Original Filed Jan. 2?, 195:5 9 Sheets-Sheet 7Qiformeg Jan. 28, 1964 E. F. ANDREWS 3,119,577

CONVERTIBLE AIRCRAFT Original Filed Jan. 27, 195 9 Shets-Sheet -sCZWEI/Vzeg 1964 E. F. ANDREWS 3,119,577

' CONVERTIBLE AIRCRAFT Original Filed Jan. 27, 1955 9 Sheets-Sheet 9Qifavweg United States Patent Ofi ice 3,119,577 Patented Jan. 28, 19643,119,577 CONVERTIBLE AIRQRAFT Edward F. Andrews, 105 15th St, BelleairBeach, Fla. Griginal application Jan. 27, 1953, Ser. No. 333,403, nowPatent No. 2,939,268, dated June 20, 1961. Divided and this applicationMay 1, 1961, Ser. N0. 106,861

7 Claims. (1. 244-7) The present application is a division of my pendingapplication Serial No. 333,403 filed January 27, 1953, now Patent No.2,989,268, in the United States Patent vOffice.

This invention relates to rotating wing aircraft and more particularlyto such aircraft having a fixed wing in addition to the rotating wing.In such aircraft the speed range is greatly extended by carrying all ornearly all the weight of the aircraft on the rotating wing duringhovering or low speed flight while all or a large part of the weight iscarried by the fixed wing during high speed flight. During high speedflight, the rotor provides little or no forward propulsion. This issupplied by a generally horizontal fluid jet. The speed is increased bymaintaining the rotor in a lightly loaded or non-lifting condition withits plane of rotation generally parallel to the flight direction. Astill further increase results from completely retracting the rotor. Toobtain good hovering and low speed characteristics, the rotor may belarge. Therefore, retraction is facilitated by first substantiallycontracting the rotor; for instance as shown in my Patent No. 2,464,285and more specifically herein. As the rotor is retractible and used onlyfor low speed flight, it should add as little weight as possible to theWeight of the aircraft. This is facilitated by driving the rotor fromthe same power plant that provides the horizontal thrust. When very highspeed is required, this may be a turbo jet power plant. In this case itis advantageous to effect the rotative drive of the rotor by compressedair issuing rearwardly from the rotor tips either with or without theburning of additional fuel at the blade ends. Such an aircraft presentsoutstanding advantages both for military and other uses as it permitshigh speed without requiring large specially prepared airports fortakeoff or landing. In fact, such an aircraft may attain near sonicspeeds and at the same time land and take off practically anywherewithout requiring any airport at all. When moderate top speed issumcient, unloading the rotor without retraction and a high speed turbopropeller or fan for horizontal thrust may be employed. The employmentof rotor jet drive creates a need for novel rotor blade constructionwhich provides a smooth unobstructed interior for the passage of fluidthrough the blade with minimum fluid losses. A rotor blade structuremeeting these requirements is herein provided, together with other noveland advantageous features.

It is an object of this invention to provide an improved rotating wingaircraft.

It is a further object to provide an aircraft of increased speed rangehaving a rotating wing for low speed flight and a fixed wing for highspeed flight.

It is a further object to provide advantageous means to eliminate orreduce the drag of the rotating wing during high speed flight.

It is a further object to provide an advantageous jet driven rotor forrotating wing aircraft.

It is a further object to provide an improved blade pitch controlconnection, and an improved sealed passage for the propulsive jet fluidfrom the fuselage to the center section and between the center sectionand the blades.

It is a further object to provide contractible and retractiblepropulsive fluid passages in a retractible rotor aircraft.

It is a further object to provide advantageous means for securinghorizontal propulsion as well as fluid jet drive for the rotor from thesame turbo power source.

It is a further object to provide satisfactory flapping and pitch changebearings and disconnectible control means, in a rotor having bladeswhich contract one above the other into the center section.

It is a further object to provide a medium speed aircraft with anon-contractible jet driven rotor supplied with propulsive fluid from aturbo-prop power plant which provides horizontal thrust for a fixed wingcarrying practically all of the weight at high speed and little or noneat low speed.

It is a further object to provide a rotor blade construction speciallysuited to pressure jet propulsion in which a smooth free passage isprovided through the blade to rearwardly directed jet outlets at theblade tips.

It is also a still further object of this invention to provideadvantageous means for realizing the purposes set forth above and in thefollowing description.

FIG. 1 is a plan view of the convertible aircraft of this invention withthe rotating wing shown in dot-dash lines in the expanded position;

FIG. 2 is a side elevation of the convertible aircraft of my inventionwith the rotating wing shown in dot-dash lines in extended position andwith a section of the fuselage cut away to show the turbo jet powerplant, etc;

FIG. 2a is a side elevation showing a separate turbine and a surroundingducted fan located immediately following the turbo jet power plant anddriven by the efiiux gases therefrom;

FIG. 3 is a front elevation corresponding to FIGS. 1 and 2 with allelements of the alighting gear extended and with the rotating wing shownextended in dot-dash lines;

FIG. 4 is an enlarged fragmentary section of FIG. 2 showing the fuselagemechanism contained therein;

FIG. 5 is a plan view of the rotating Wing partially broken away shownextended and cross-wise of the fuselage;

FIG. 6 is an enlarged view of the retraction and extension mechanismshown in the retracted position;

FIG. 7 is an isometric view showing an enlarged portion of the controlmechanism enlarged;

FIG. 8 is a cross section of the rotating wing, including the shaft,fluid passage, and blades;

FIG. 9 is an enlarged cross sectional fragmentary View of the flexibleconnection;

FIG. 10 is a plan section through one end of the center section showingthe inner end of the blade mounted on its carriage;

FIG. 11 is an isometric sectional view showing the construction of theblade;

FIG. 12 is a rear view of the blade tip;

FIG. 13 is a section taken on the line 1-313 of FIG. 12;

FIG. 14 is a modification of the blade tip of FIG. 13 adapted for bladetip combustion;

FIG. 15 is a plan view partially in section of a modification in whichthe blades are not contractible;

FIG. 16 is a sectional view taken on the line -1616 of FIG 15;

FIG. 17 is a side view of the rotating wing of this modification inwhich parts are cut away and other parts shown in section;

FIG. 18 shows a further modification in which the expansion andcontraction of the blades into the center section is effected by themotor driven drum and cable mechanism;

FIG. 19 is an embodiment showing a cyclical pitch change mechanism inwhich the center section is universally jointed to the shaft;

FIG. 20 is a plan view of a modification of the rotating wing in whichthe blades lie generally in the same plane and in which the blades areshown contracted;

FIG. 21 is a similar view showing one end of the center section with theblade expanded;

FIG. 22 is an end 'view of this embodiment showing both blades mountedon top of the blade carriage support plate; and

FIG. 23 is a diagram showing an angular relation between the fuselagemajor axis, the chord of the fixed wing and the axis of the rotor whichmay be employed.

Referring to FIGS. '1, 2, and 3, the fuselage 16 of the convertibleaircraft is provided with a depression 12. A contractible rotating wing14 is mounted for rotation on the fuselage at the center of thedepression 12. The rotating Wing 14 is retractible into the depression12 after the blades 16 have been contracted within the center section18, as shown in full lines in FIG. 2. The rotating wing 14 may also beelevated above the fuselage and the blades 16 expanded so that theyextend outwardly from opposite ends of the center section 1-8 as shownin dotdash lines. The center section 18 is pivotally mounted at the hubfor flapping motion. The embodiment of the convertible aircraft shown inFIGS. 1, 2, and 3 is equipped with swept-back wings 20 of relativelysmall area which are adapted to high speed flight when the aircraft isbeing propelled by the forward thrust of its turbo jet engine 22 withthe rotating wing retracted. The wings 20 are provided with ailerons 21.

At the rear of the fuselage 10 is a swept-back elevator surface 24having elevator flaps 25 and twin vertical rudders 26, one at each endof the elevator. Due to the backward sweep of the elevators and theemployment of two rudder s26 and corresponding fin surfaces at the outerends of the elevator, clearance is provided so that when the blades 16are fully extended and flap downward around the flapping pivot as itpasses the tail, it will clear the vertical fins and twin rudders 26. Itwill be seen that by the employment of the swept-back elevator inconjunction with the twin rudders located at the ends thereof, clearanceis provided for a larger diameter rotating wing without undue rearwardextension of the fuselage.

The rudders 26 are linked with jet rudders 28 by means of linkage 30.The rudders 26 and 28 are operated simultaneously by the control member32 which may run to rudder pedals 34 in front of the pilots seat 36. Themain purpose of the jet rudders 28 is to provide control in yaw duringslow speed operation when the weight of the aircraft is supported whollyor mainly by the rotating wing 14. Even though the aircraft is hoveringand there is no relative air flow over the rudders 26, yaw control isprovided by the high speed jet issuing between the jet rudders 28. Theair intake of the turbo jet 22 may be located at the nose of thefuselage and the air conducted rearwardly to the turbo jet by bifurcatedpassages 38 which diverge around the pilots seat, alighting gear, androtating wing support, and converge again at the front of the turbo jetengine.

If desired, flush type twin air intakes on each side of the fuselage maybe provided instead of the nose intake. The alighting gear is of thebicycle type. Two wheels 49 are provided to the rear of the center ofgravity. Two supporting members 42 spaced apart sufliciently to clearthe bottom supports are pivoted near the bottom of the fuselage, so thatthe wheels may retract forwardly and upwardly into the fuselage. A frontwheel 44 is provided which may retract backwardly and upwardly into thefuselage, as shown in FIG. 2. Two balancing wheels 46 are pivotallyconnected by struts 43 to the wings 20. The wheels 46 are resilientlymounted, so that practically all of the weight of the aircraft issupported on the wheels 40 and 44, the Wheels 46 merely acting tomaintain the aircraft in an upright position without carrying a largeweight. They therefore can be made small to retract readily into a thinhigh speed wing. {The rotating wing when extended may be rotated bymeans of air jets issuing backwardly from the tips of the blades 16. Thecompressed air for the rotor drive may be supplied from the compressor50 of the jet engine 22. As the speed of the convertible aircraft isslow during operation of the rotating wing, the power which the jetengine 22 must supply for horizontal propulsion is relatively small.Therefore air may be bled from the compressor 50 to drive the rotatingwing while adequate thrust for low speed forward propulsion may still beprovided. When the rotating wing is retracted, the fixed wing 20sustains the weight of the aircraft for high speed flight. At this time,the valve 52 is closed and no air is diverted from the jet engine whichgives its maximum forward thrust for high speed flight.

Referring to FIG. 2a, an alternative arrangement is there shown whereina separate turbine 22a is used immediately following the turbocompressor power plant and driven by the efflux gases therefrom to drivea ducted fan 22b to augment the forward jet thrust supplied by the turbojet power plant. As is apparent, the efiiux gases from the jet enginecombustion section 58, after passing through the compressor turbine,pass through the blades of the separate turbine 22a driving it. A ductedfan 22b is mounted on the outer rim of the separate turbine and rotatestherewith on common central bearings. The duct 22c in which said ductedfan is mounted receives outside air through the forward inlet end of theduct and the same is discharged rearwardly by the ducted fan 22baugmenting the jet thrust. When the rear of the fuselage 10 is notsymmetrical with respect to the axis of the turbojet power plant,indentations in the fuselage (not shown) may be provided to admit airall around the intake of the duct 22c. An intake to the duct less than afull circle might also be employed. The jet rudders 28 shown in FIG. 2may also be incorporated.

Referring to FIGS. 4 and 6, the air conduit 54 is connected at one endto the passage 56 which joins the outlet of the compressor 50 to the jetengine combustion section 58. It will be seen that the valve 52, whichcan be controlled from the pilots position 36 by means of the connectingmember 60, closes off the communication from the passage 56 to theconduit 54 when in the closed position as shown. When the valve 52 ismore or less open, air compressed by the compressor flows through theconduit 54 and into the telescoping passage 62, the top end of whichconnects to the stationary element of the sealing chamber 65. This maysurround at the top end the rotating element 66 of the sealing chamberwhich rotates with the rotor shaft 68. The rotating element 66 isconnected by the flexible connection 70 to the center section flangemember 72. This forms the air connection to the center section 18through which air is supplied to the tip jets to rotate the blades 16.The connection between the sealing chamber and top element 66 isrotative, and at least one sealing member 74 is provided to minimize airleakage between them. The joints between the members through which thecompressed :air passes should of course be highly resistant to airleakage.

If desired, vaporized fuel may be delivered into the passage 54 from therotor fuel nozzle 55 to increase the thrust of the rotor jets with agiven air flow from the compressor 50 through the valve 52. This can beeffected by opening the fuel valve 57 by means of the control member 59extending to the pilots position. This fuel may be supplied to the rotorfuel line 61 from the fuel pump and fuel supply (not shown) of the turbojet engine 22. A separate rotor fuel pump driven from the turbo jetengine 22 and connected to the turbo jet fuel supply may be employed,alternatively. The rotor fuel line 61 connects to a vaporizer passage 63which may be placed around the outside of the combustion chamber, asshown, or around the jet exhaust, or in the tail cone. When the rotorfuel valve 57 is open, fuel flows through this vaporizer passage and isvaporized by the heat supplied from the combustion chamber or the jetexhaust.

The vaporization of the fuel is thus accomplished mainly by employingwaste heat from the turbo jet engine. The vaporized fuel then issuesfrom the rotor fuel nozzle 55 and mixes with the air in the passage 54.It is then conveyed to the rotor jets. at the blade tips, together withthe compressed air, as previously described. The provisions required forburning the fuel air mixture at the blade tips will be later described.

The rotor shaft 68 is carried on the elevating member 76 by means ofball or roller bearings; for instance as shown in FIG. 3 of AndrewsPatent No. 2,511,687. The elevating member 76 is mounted on three screwshafts 78. These are in turn rotatively mounted and supported in topplate 82 and fastened at the top and the bottom of the fuselagerespectively. A sprocket 84 is fixed at the bottom of each of the screwshafts. An endless sprocket chain 86 surrounds and connects the threesprockets 84. On one of the shafts 78 is a worm gear 88. An electricmotor 90 is mounted on the base plate 80 with its. shaft perpendicularto the screw shaft. The shaft of motor 90 carries a worm which engagesthe worm wheel 88 to rotate the screw shafts 78 simultaneously in onedirection or the other. Conductors 92 run to appropriate controls in thevicinity of the pilots seat to cause the motor 90 to stop or run ineither direction. iBy causing the motor 90 to rotate in one direction,the screw shafts '78 rotate in appropriate nuts 94 in the elevatingmember 76 to raise the rotating wing to its extended position as shownin FIG. 4 or lower it to its retracted position on top of the fuselagecenter, as shown in FIG. 6.

When the elevating member 76 is in its top position, the telescopingpassage 62 is raised so that it extends into the chamber '64 only asufiicient distance to effect a tight air seal. When the member 76 is inits lowermost position, the passage 62 telescopes into chamber 64. The

sealing chamber 65 is mounted at the top' of the elevating member 7 6.Supporting members 96 are fixedly mounted on the member 76 and chamber65. The members 96 engage a sealing plate 98. When the rotating wing isretracted, the sealing plate 98 lies at the bottom of the depression 12in the top of the fuselage into which the rotating wing 14 retracts.When the rotating wing is extended, the members 96 engage the plate 98and raise it into firm contact with the inside of the fuselage skin, asindicated at points 100. This smoothly seals the top of the depression12 when the rotating wing is extended, to reduce drag.

The sealing plate 93 is made in such a way as to be quite rigid in thedirection of the major axis of the fuselage, but is flexible laterallyso that when it is in the extended position as shown in FIG. 4 it willassume a convex form to match the curve of the fuselage. When it is inthe retracted position as shown in FIG. 6, it will bend into a concaveform lying closely against the concave bottom of the depression 12provided in the fuselage for accommodating the retracted rotating wing14.

In front of thet pilots position 36 is located a control lever 102 whichmay control the pitch and roll of the convertible aircraft both in thefixed wing and rotating wing flight regimes. In the fixed wing flightregime this lever 102 controls ailerons 21 for roll and the elevatorflaps 25 for pitch. The control lever 102 is mounted at the bottom foruniversal movement. A gimbal ring 104 is provided for this purpose. Thelever 102 is pivoted to the ring 104 by the pivot pin 106. The ring 104is in turn attached to the swinging members 108 by pivot pin 110 atright angles to the pivot pin 106. A connecting member 112 is connectedto the bottom of the lever 102 immediately above the ring 104. Themember 112 carries a cross member 114. A universally mounted fixed wingcontrol member 116 is mounted to the fuselage by a base member 113 andis universally movable relative thereto by means of a gimbal ring 120.The elevator flap cables 122 are connected to cross arms 124. A secondpair of cross arms 126 are mounted on the fixed wing control memberperpendicular to the cross members 124. The aileron control cables 128connect to the cross arms 126. The two perpendicular axes of the gimbalring are coextensive with the two cross arms 124 and 126. On therearward cross arm 124 is a cross member 130. The cross member 114 isconnected to the cross member 130 by means of connecting members 132attached by four ball and socket joints. It will be seen that if thelever 102 is moved forward or backward, it will cause the cross arms 124to rock around one gimbal axis while the cross arm 126 does not rockbecause it is coextensive with the axis around which the rocking motiontakes place. Thus the forward motion of the lever 102 opcrates theelevator flap 25 to produce downward pitch while the backward motion ofthe lever 102 moves the flap to cause upward pitch. On the other hand,if the lever 102 is moved sideways, cross arms 126 are caused to rock,while the cross arms 124 do not have this motion because they are nowcoextensive with the gimbal axis around which the motion occurs when thelever 102 is moved sideways. The rocking motion of the cross arms 126causes the depression of the right aileron and the elevation of the leftaileron 21 when the lever 102 is moved to the left. It will beunderstood that the cables 122 are connected to the elevator flaps 25and the cables 12% are connected to the ailerons 21 in wellknown manner,so as to produce the operation as above described. It may be pointed outthat the links 132 and the swinging members 108 are provided so that abodily movement of the lever 102 and the gimbal 104 forward and backwardwill not affect any control movement of the fixed wing control member116. A forward and backward movement of the control lever 102 and thegimbal 104 occurs as a result of extending or contracting the rotatingwing 14 as will be described.

A shaft 134 carries at one end a yoke 136. The other end of this shaftis fixedly mounted to a pivot member 139 which is in turn pivotallyconnected to lever 141. A tubular member 142 is slidably mounted on theshaft 134. The tubular member 142 is provided at one end with a slottedarm 144. Slotted arm 144 is connected to the lever 102 by a pin 146passing through the bifurcated and slotted end of the arm 144. Thus whenthe lever 102 is rocked backward and forward the tubular member 142slides back and forth on the shaft 134. At the other end of the tubularmember 142 is a bifurcated arm 149 which is connected to the universallymovable rotating wing control member 150. The arm 149 is connected tothe member 150 by means of a pivot pin 152 passing through thebifurcated ends of the arm 149 and the hole in the lever 150. Thus itwill be seen that a fore and aft movement of the lever 102 causes acorresponding movement of the lever 150, while a sideways movement ofthe lever 102 also causes a corresponding sideways movement of the lever150. The lever 150 is connected to the lever 163 by means of a ball andsocket joint 156. The lever 163 corresponds to the lever 168 shownespecially in FIG. 3 of Andrews Patent No. 2,511,687, and

the wabble plate 148 connects to the lever 168 in substantially the samemanner as shown in that patent, and therefore need not be describedfurther.

The control rods 133 shown in FIG. 8 correspond to the control rods 13%of the above mentioned patent and are connected to the brackets 140 inthe same general way through the wabble plate 148 to the lever 168. Therods 138 therefore affect pitch and roll control of the rotating wing 14during the rotating wing flight regime and corresponding movements ofthe lever 102 produce the same pitch and roll control effects aspreviously described in connection with the fixed wing controls. It willbe seen that the lever 141 is pivotally mounted on a control supportmember 158. This member is mounted for sliding motions on the screwshafts 78 and is connected by tubular connecting members to theelevating member 76. It will be seen that when the rotating wing isextended and the elevating member 76 moves to its up position,

the control support member 158 will move upward with it. As the yoke 136is connected to the gimbal ring 104 and the lever 102 by the pin 110,the upward movement of the control support member 158 will cause thelever 102 and gimbal 104 to move forward as a whole. This motion movesthe swinging members 108 forward around the pivot 163 which is connectedto the fuselage by the hinge member 164. This motion is transmittedthrough the shaft 134 and/or the tubular member 142. On the other hand,when the rotating wing is retracted and the elevating member occupiesits lowermost position, the control support member 158 moves downwardand the lever 102 and gimbal ring 104 move backward bodily. However, aspreviously described, this motion does not affect the movement of thecontrol lever 102 around its universal pivotal point so that noinfluence is exerted on either the fixed or rotating wing controls bythe retraction or extension of the rotating wing.

The swinging movement of the lever 168 by the lever 150 affects thedifferential cyclical pitch changes in the rotor blade angle to causepitch and roll, while the vertical movement of the never 168 by thelever 150 affects collective pitch control by a vertical movement ofwabble plate 148 and collective pitch sleeve 162 by imparting asimultaneous vertical movement to the rods 138.

The lever 166 at the pilots position 36 controls the collective pitch ofthe blades of the rotating wing. This lever carries a bevel gear 170 atits pivoted lower end which meshes with a bevel pinion 172. This pinionis connected through a universal joint 174 with a shaft 176. The otherend of the shaft 176 is provided with a splined bore into which asplined sliding rod extends which carries a second universal joint 180,the other end of which connects to a worm gear 182. This worm gearmeshes with a worm gear sector 184 on the pivoted end of the lever 141.The worm 182 and sector 184 are so constructed that when the lever 166is moved forward, the collective pitch of the rotor blades 16 is reducedand when this lever is moved toward the rear the collective pitch isincreased.

This is effected by the corresponding upward and downward movements ofthe lever 141 around the end which is pivoted to the control support158. The movement of the lever 166 causes the rotation of the shaft 176and the worm 182 which in turn moves the lever 141. The universal joints174 and 180 and the sliding spline rod 178 permit the elevating member76 to move to the extended or retracted position without affecting thecollective pitch control. At this point attention is called to the factthat a movement of the control lever 102 always produces thecorresponding motion of the fixed wing controls. However, when theblades 16 are contracted into the center section 18, as will bedescribed later, the blades 16 are fixed at approximately the angle ofzero lift, and the pitch change connections between the blades 16 andthe control rods 138 are disengaged at the outer end of the centersection so that after the blades have been contracted a short distance,the movement of the control lever 102 and the lever 168 has no effect onthe pitch of the blades. This is also true of the collective pitch lever166.

The contractible rotating wing, shown in detail in FIGS. 5, 8, 9, and10, is of the type shown in Andrews Patent No. 2,464,285 (FIGS. 1 and2). The center section 18 comprises an outer shell 166 of sheet metalsuch as Dural. Shell 186 is secured to I-beam members 188 running fromone end to the other of the center section. A blade carriage supportmember 190 also runs from one end to the other of the center section,and is secured to and between the I-beams 188. The I-beams are securedon the lower side of the center section near its center to the centersection flange member 72. The member 72 is sufiiciently wide to besecured, for instance by rivets, to the I-beams 188 along a substantialportion of their length, as shown in FIG. 5, to provide a strong 8attachment between the center section flange 72 and the blade carriagesupport through the I-beams 188. The firm attachment of the shell 186 tothe I-beams 188 forms a rigid center section assembly with a smooth lowdrag exterior and of relatively light weight.

The blades 16 are mounted on movable carriages 192 which in turn areslidably mounted on the carriage support member 190. The carriages 192are movable from the expanded blade position, as shown in FIG. 5 andFIG. 10, with the blades outside extending outward from the centersection, to a contracted position in which each carriage 192 moves tothe opposite end of the center section and the blades 16 are coextensivewith the center section 18. To permit this motion, one blade andcarriage must move in a plane above or below the other. Thus onecarriage 192 and blade 16 are positioned above the carriage supportmember 190 and the other below it. The center section flange 72 isprovided with two bearing members 194. The shaft 68 carries at its upperend a yoke 196 equipped at each end with bearings 198. Pins 200 extendthrough corresponding bearings 194 and 198 and needle rollers may beprovided between the bearings and pins if desired to reduce friction.These bearings constitute the attachment of the rotating wing 14 to theshaft 68 and also constitute the flapping axis of the rotor. Aspreviously described, the flange 72 is connected to the rotating element66 of the sealing chamber by the flexible connection 70 which seals thepassage for compressed air from the sealing chamber 66 into the hollowinterior of the center section 18. Thisflexible connection isconstructed of flexible material such as a silicone or other plasticwith continuous wire rings 202 embedded at the inner and outer edges ofpleats therein to resist expansion by the internal air pressure. Thisflexible member 70 permits the flapping of the center section around thebearing pins 200 and still maintains a leak-proof air passage. It may bepointed out that the top element of the sealing chamber 66 is rigidlyconnected to the yoke 106 by support members 204. These insureconcentricity of the element 66 and the element 65 of the sealingchamber and result in minimum obstruction to the free flow of air. Thecontrol rods 138 are connected at the top to pitch control levers 206.These levers 206 are mounted on the inner ends of shafts 208 whichextend from the center to both ends of the center section. These shafts208 are mounted in bearings at their inner ends. Each end of the centersection is provided with an end plate 212. A second set of bearings iscarried one by each end plate, and the outer ends of the shafts 208 arecarried therein. Fixed to the outer end of each shaft 208 is a sector210. One of these sectors 210 has substantial axial length and mayextend a predetermined distance inward on shaft 208. The other of thesesectors engages an idler sector 215. The sector 215 engages a secondidler sector 214 which in turn engages sector 216 carried by the upperblade 16. The part of sector 214 engaging sector 216 also hassubstantial axial length. The long sector 210 engages the correspondingsector 216 connected to the lower blade 16. The upper sector 216connected to the upper blade 16 engages the long idler sector 214. Theconnection of the long sector 210 and the long idler sector 214 with thesectors 216 is disconnected when the blades are contracted into thecenter section, thereby freeing the rotating wing control levers 102,166, and 168, as previously described.

The blades 16 are connected at their inner ends to blade root members218 which may be attached to the outer blade structure in a manner laterto be described. It may be said, however, that the outer blade structureis torsionally rigid with respect to the blade root member 218 so thatthe rotation of this member causes the pitch of the entire blade tochange correspondingly. The blade root member 218 is hollow and has areduced diameter to fit the inner race of the outer pitch change bearing220. Farther toward the end, the diameter is reduced again to take theinner pitch change bearing 222. Beyond this hearing the member 218 isthreaded for a retaining nut 224 which clamps the inner race of thebearing 222. The bearing 222 may be of the double row ball bearing typeadapted to take the centrifugal thrust of the blade. A sleeve 226 isinterposed between the inner races of the bearings 220 and 222 so thatboth of the inner races are clamped by the nut 224. Just outside of thebearing 220 the pitch control sector 216 is fixedly mounted on the wingmember 218 so that when the shaft 208 is rotated and the sectors 210 and214 are meshed with their corresponding sectors 216, the pitch of theblades 16 changes accordingly. The outer races of the bearings 220 and222 are mounted in bearing-retaining sockets 228 and 230 in the carriage192. The outer race of the bearing 220 is retained by the retaining nut232, and the outer race of the bearing 222 is retained by the retainingnut 234. Thus the blade root member and the blade are securely mountedfor pitch change rotation around the aerodynamic center of the blade 16.The carriage 192 is provided with two horizontal positioning rollers 236which revolve on pins fixed to the carriage. These rollers fit closelyin and against the side walls of a T-channel 238 in the carriage supportplate 198. Thus the carriage is securely held against sidewise motionwhile being free to move from one end of the center section to theother.

Two pairs of rollers 240 are also held on pins fixed to the carriage.The axes of these rollers are horizontal and they are of such diameteras to fit closely with only slight clearance against the top and bottomof the T-slot channel. All surfaces of the T-slot channel are smooth andregular to permit ready endwise movement of the carriage. The rollers240 position the carriage securely in a vertical direction. Thus theblade 16 is positioned securely with relation to the center section 18except that the blade is free to move in and out of the center sectionon its carriage and to change its pitch by means of the bearings 22!)and 222.

The carriage 192 is also equipped at one end with a cross-shaft 242mounted to the carriage by means of bearings 244. The carriage supportplate 190 is also provided with tracks 246 and corresponding racks 248,both of which extend nearly to the ends of the carriage plate 190, therebeing one set above the plate for the upper carriage and a second setbelow the plate for the lower carriage. The cross-shaft 242 is providedat each end with a roller 250 engaging the track and a gear 252 engagingthe corresponding rack. The diameter of the roller 258 is such that whenit is in contact with its track 246, the pitch diameter of the gear 252corresponds to the pitch line of the rack 248. Fixed to one end of thecross-shaft 242 is a worm wheel 254. An idler shaft 256 carries a worm258 at one end which engages the Worm wheel 254. At the other end of theidler shaft is a worm wheel 268. The idler shaft is carried in bearingssecured to the carriage 192. An electric motor 262 is fixedly mounted toone side of the carriage 192. The shaft of this motor carries a wormgear 264 which engages the worm wheel 260. It will be seen that thisarrangement provides a high reduction ratio from the motor shaft wormgear 264 to the cross-shaft 242. The motor is designed to provide hightorque and for high rotative speed. It will be seen that the operationof the motor in one direction will cause its carriage to move toward oneend or the other of the center section 18 carrying its blade 16 with it.The motors on the upper and lower carriages are so connected that theupper and lower carriages always travel in opposite directions. Theupper and the lower carriages are connected together by a chain or cable268 securely anchored to both carriages at 270. This cable passes aroundthe pulleys 272 mounted on pins 274 fixed to extensions of the carriagesupport plate 190. Thus the two lengths of cable 268 are anchored one toeach end of each carriage 192 so that the cables and the carriages forman endless cable system,

the purpose of which is to insure the equal and opposite motion of thetwo carriages 192 and their respective blades 16. Thus the rotativebalance of the rotating wing 14 is maintained regardless of theexpansion or contraction of the blades.

Current may be supplied to the motors 262 by means of conductors (notshown) running from a power supply and reversible switch means locatedin the fuselage through slip rings and flexible connections to thecenter section and by means of rails engaged by sliding brushes on themotors. It will be seen that the rails 246 and the racks 248 end at apoint somewhat inboard of the ends of the center section 18. A stop 276is also provided against which the rollers 258 may stop when the bladesare fully extended to guard against further outward movement. It may benoted that the center section should be made air-tight so as to avoidleakage of air supplied to the tip jets. A moderately close fittingopening is provided in the end plate 212 through which the blade 16projects. An outer end plate is also provided with a corresponding closefitting opening, thus providing an additional seal outside the pulleys272. For a short distance outward from the inner end of each tipsection, a flexible surface 282 of the blade is provided, and the ribs280 are mounted for free rotation upon the round portion of the bladeroot member 218. The surface 282 is secured at its outer end to theremainder of the blade structure so as to form a continuous airfoilsurface. At the inner end of the flexible surface 282, a flange 284 isprovided which forms an air-tight seal against the end plate 212, beingforced into close contact with it by the internal air pressure. Thisflexible surface section 282 permits the pitch of the blade 16 to bechanged relative to the cord of the center section 18 and stillpreserves an unobstructed air-tight passage for the tip jet air from thecenter section into and through the blades. Due to the axial length ofthe sectors 218 and 214 they remain in mesh with the sectors 216 untilthe blades 16 are retracted into the center section 18, a distancegreater than the length of the flexible sections 282. Thus the pitch ofthe blades 16 is always determined either by the meshing of the pitchcontrol sectors or, when these unmesh, by the entry of the rigid innerportion of blades 16 into the close fitting openings in plates 212 and278 of the center section 18.

The blade 16 is constructed so as to form a free and smooth passage forthe compressed air through the blade from the center to the tip where itissues as a rotor propelling jet. The construction of the blade is shownin FIGS. 11 to 13, while FIG. 14 shows a modification of the tip inwhich fuel may be burned in the air stream immediately before it issuesfrom the tip jets. To minimize frictional losses due to the rapid fiowof fluid through the interior of the blade, internal obstructions andirregularities should be avoided as far as possible. Lightness, strengthand ease of fabrication are also desired.

The blade root 218 is shown in FIG. 10. At its outer end there is atransition from a round to a square or rectangular cross section. Thesquared end projects into the inner end of the blade 16 and is securelyfastened thereto by rivets or other securing means as shown in FIG. 11.The blade itself comprises a group of long sheets bent the long way intoshells which may be of strong, light material such as Dural or plastic.The shells fit one within the other to form a nested assembly. Theleading edge shell 286 may be of the thickest metal. This has aD-section, the forward portion having the nose shape of the aerofoil andthe rear portions being lapped over one another to form a straightvertical rear wall. The second shell 288 is of similar shape, withvertical back wall formed in the same manner, but extends fartherrearwardly in a cordwise direction and may be of thinner sheet metal.The third shell 290 is similarly constructed but is still longercordwise and made of thinner material. The fourth shell 292 is similarlyconstructed but the rear vertical walls are shorter in a verticaldirection, as this shell extends well toward the trailing edge of theaerofoil. The fifth and outermost shell 294 forms the exterior of theblade and is of exactly the aerofoil section employed. The rear edgesinstead of being bent into a vertical rear wall are secured to eachother without being bent to form the trailing edge 296 of the aerofoil.

As shown in FIG. 11, these five shells are inserted one into the other,the first shell being the innermost and the fifth and last shell theoutermost. These shells may be of uniform section from root to tip andthey may be fastened together into a rigid unitary structure by anydesired means such, for instance, as spot welding, riveting, or cyclewelding by means of strong durable adhesives. For instance, the outersurface of the first shell and the inner surface of the second shell maybe thinly coated with a suitable adhesive before the first shell isinserted into the second or before the second is bent around the first.The same procedure may be followed in assembling the third, fourth, andfifth shells into a unit with the first two.

After each of the first four shells has been formed, the outside of onerear vertical wall and the inside of the other may be similarly coatedwith adhesive and pressed firmly together with or without heat to formeach shell into a hightly closed tube. The square portion of the bladeroot member 218 may also be similarly coated and inserted a considerabledistance into the blade between the rear wall of the first shell and therear wall of the second shell. The first two shells 286 and 288 may beso proportioned that the center of the space between their rear wallscorresponds to the quarter cord point or a point forward of theaerodynamic center. Thus the pitch change bearings 229 and 222 establisha pitch change axis near the aerodynamic center of the blade. Rivets 298may be employed additionally to secure the blade root member to thefirst and second shells. Additional rivets 300 may be employed above andbelow additionally to hold shells 283, 290, 292, and 294 to the bladeroot member 218 and to each other. Although five shells have beendescribed, it will be understood that a greater or lesser number may beemployed as desired. It will be seen that the first shell encloses aninternal gas passage 302, the second shell encloses a gas passage 304,the third shell a gas passage 306, and the fourth shell 2. gas passage303. The fifth shell 294 encloses a relatively thin space 310 adjacentthe trailing edge having only a small cross sectional area, and the flowof fiuid to the tip jets may be excluded from this space. It may bepointed out that a blade or wing which tapers in thickness from root totip may be made employing the above described type of construction. Ifthe taper is straight, the shells can be bent to shape and nested withadhesive between as above described.

flhe flexible surface 232 extends outwardly and is abutted against theshell 294. The rib 280 may be located at the end of the surface 282where it abuts against the shell 294. The joint between the two may besealed with a suitable plastic so as to form a continuous outer surfacehaving the same section as the shell 294. Fluid under pressure is freeto pass from the center section 18 into the inner end of the bladesthrough the flexible surface 282 and thence through the passages 382,394, 306, and 308 to the blade tip 312.

The tip 312 is rounded and slanted backward as shown in FIGS. 12 and 13.The walls of the various passages 302, 304-, 306, 30 8, and 319 arecurved backwardly as shown in FIG. 13 to direct the fluid flowrearwardly so that the reaction from the backward flow will provideforward propulsion for the blade tip. Th se rearward openings formrearwardly directed nozzles from each of the passages having outletareas substantially smaller than the area of the corresponding passageso that the flow of ilu-id inside the passages will be substantiallyless than the velocity of the jet issuing from the openings. Due to thebackward slant of the wing tip, the forward jet passage 392 overlaps thejet passage 304. The jet passage 306 is likewise displaced inwardly withrespect to the jet passage 304, and so on, to the rear. Thus each jetclears the jet rearward of it. As shown in FIG. 13, defiectinig sections314 may be positioned as shown for instance in the passages 392, 306,and 36 8, more efficiently to direct the fluid rearwardly. The innershells may also be progressively cut oif at the tips as much as isconsistent with adequate strength and balance to lighten the tip.

FIG. 14 shows a modification of the blade tip to adapt it for theburning of fuel in the blade tip to secure additional thrust from thetip jets with a given supply of fluid to the tips by heating this fluidand increasing its volume and its discharge velocity. The tip as shownin FIG. 13 may be cut off a substantial distance from the end forinstance on the line 316 in FIG. 14, and a new tip 318 substitutedtherefor which may be secured to the blade 16 by any suitable means,such, for instance, as the rivets 320. The tip 318 may be made of ametal or alloy adapted to stand the high temperatures of the combustioninside the tip. The deflectors 322 may be welded in or otherwisefastened by means which will withstand the temperatures. A spark plug324 is provided as shown for igniting the combustible mixture of air andfuel supplied to the tip through the blade. Flame guard partitions 326may also be added to prevent the flame from travelling inwardly into theblade. The length of the tip 318 may be sutfioient to perm-it thesubstantial completion of combustion within the tip, A high tension lead330 secured to the wall of the passage 310 may be employed to deliverhigh voltage energy to the spark plug 324 to provide ignition. Aftercombustion is started and the tip 313 has heated, the spark may bediscontinued.

The combustible mixture is supplied to the combustion space Within thetip 318 by opening the rotor fuel valve 57, as shown in FIG. 4, so thatfuel passes into the vaporizer 63 and issues as vapor from the nozzle 55where it mixes with the proper amount of air in the passage 54 and iscarried through the sealing chamber 65 into the center section 18,thence into the inner end of the surface 282 and shell 294- and throughthe four passages to the combustion space within the tip 318. The airfuel mixture may be adjusted by proper operation of the fuel valve 57and the air valve 5 2.

The operation of the embodiment of FIGURES 1 to 14 inclusive may be asfollows: assuming that the aircraft is on the ground with its rotor 14contracted and retracted as shown in full lines in FIGURES 1, 2, 3, and6. After the turbo jet engine 50 has been started, the electric motor isstarted and rotates the screws 78 until the rotor support member 76 israised to its extended position as shown in dotted lines in FIGURES 1, 2and 3 and in full lines in FIGURE 4. The rotor air valve 52 is thenpartially opened by means of control rod 60, the speed of the turbo jetengine having previously been increased to a suitable amount byappropriate advance of its fuel control throttle. Compressed air is thendelivered from the turbo jet compressor outlet 56 through the passages54, 64-, 62, 65, 66 and 70 to the center section of the rotor 18 andthence into the flexible inner end 282 of the blades 116 through theblade passages, 392, 304, 306, 308 and 310, FIGURE 13, and outrearwardly through the blade tip propulsive passage 314. This causes therotation of the rotor 14. When the desired rotative speed is reached theblade extension motors 262 may be started in the proper direction toextend the blades 16 out of the center section 18 to their maximumdiameter. When fully extended the motors are stopped either manually orautomatically, for instance by limit switches (not shown). Meanwhile,the rotor air valve 52 and the turbo jet throttle may be advanced tosupply additional air to bring the rotor up to the desired speed. Itwill be seen from FIGURES 8 and 10 that the rotation of the motors 262in the proper direction rotate the worm gears 264,

the meshing Worm wheel 26%], and the Worm 258 which is fixed to the wormwheel 2651*. The (worm wheel 254 meshes with the worm 258. The crossshaft 242 is driven by the worm wheel 25 4 and in turn drives thepinions 252. These pinions engage the twin racks 24S and the rotation ofthe pinions in the proper direction moves the blade carriage 192outwardly carrying the blade with it. As the blade carriages 192 reachthe :outer end of their travel, the pitch control sectors are which moveout ward'ly with the carriage engage and mesh with stationary pitchcontrol sectors 21% and 2114. As the blades .16 are now fully extendedfrom the center section, movement of the cyclical pitch control lever192i will now effect differential pitch change of opposite blades 16while the movement of collective pitch lever 165 will effect collectivepitch change of the blades. It may be noted that the position of theblades 16 while they are only partially extended from the center sectionis such that they are held firmly at zero angle of incidence while theweight of the aircraft is supported by the fixed wing. If the pitchcontrol lever 162 is neutralized and the collective pitch control lever165 is in the zero lift position as the blades 16 approach the fullyextended position, the movable sectors 216 will mesh properly and freelywith the stationary sectors 21% and 2.14. The pitch control leversshould therefore be moved to these positions as the movable sectorsengage the pitch control sectors.

The aircraft is now ready to take off as a helicopter when the rotor 14driven by the tip jets has been brought up to the proper speed. If thecompressed air supply available from the turbo jet engine St issufiicient, the rotor may be brought up to the proper speed by merelyopening the rotor air valve 52 and the turbo jet throttle to asufficient extent. Under these circumstances the direct discharge of the:air from the tip jets as shown in FIGURES 12 and 13 is alone employed.This requires a relatively large delivery of air from the turbo jetcompressor. However, this air may be available if a turbo jet compressorpower unit is employed large enough to provide sufficient thrust forvery high speed fixed wing fiight. The quantity of air supplied by thecompressor may be greatly reduced or more rotor power may be suppliedwith a turbo jet compressor of given capacity if additional fuel isburned in the air delivered to the blade tips as shown in FIGURE 14.When this arrangement is employed the tip jet fuel valve 57 is opened bymeans of the control to allow fuel to flow from the fuel supply 6 1through the vaporizer 63 where it is vaporized, for instance by thewaste heat from the turbo jet exhaust passage. The vaporized fuel isthen discharged from the nozzle 55 into the rotor air passage 54. It iscarried from this point, together with the air, to the blade tips aspreviously described for the compressed air alone. A correct mixture forburning in the tips may be supplied either by manual or automaticadjustment of the controls 59 and 60 relative to each other. Theautomatic adjustment of these controls may be effected, for instance inthe manner shown in the Doblhoff Patent 2,540,190. Delivery of fuel tothe blade tips already mixed with the combustion is particularlyadvantageous where a contractible rotor, such as that herein described,is employed as it would be difficult to deliver the unmixed fuel to theblade tips with contractible blades. The pre-mixing of the fuel with theair is also advantageous in that greater time is available for propermixing and the effect of centrifugal force on solid fuel lines is alsoavoided. The fuel air mixture delivered to the blade tips may be ignitedby the spark plug 324, and the combustion may be confined to the tips bymeans of suitably positioned flame arrestor partitions 326. The ignitioncable 334 may be led inward and fixed at the forward end of the passage319, which is small in area and is not needed to carry the fuel airmixture. It may be pointed out that as shown in FIGURE 14 the walls 318of the tip chamber in which combustion takes place should be suitablymade of a heat resisting alloy capable of standing the high heatgenerated by the burning of the combustible mixture. When combustion ofadditional fuel is effected in the blade tips in accordance with FIGURE14, a given jet velocity can be obtained from jet openings of given areawith a much smaller volume of air delivered to the combustion chamberbecause of the expansion of the air due to the heat of combustion. Dueto the fact that the air is relatively cool when passing through theblades and the passages connecting the blades with the compressor, thevelocity through these passages for a given mass flow and the attendantfrictional losses are reduced. There is still further reduction in thisvelocity compared to the jet velocity as the area of the passages on thecompressor side of the combustion chambers are large compared to thearea of the tip jet opening. The amount of air which must be bled fromthe turbo jet compressor to provide the desired amount of propulsivethrust at the rotor tip may be very substantially reduced by the burningof fuel at the blade tips. It will be understood that when air is bledfrom the turbo jet compressor to drive the rotor, the forward thrust ofthe turbo jet will be greatly reduced. However, no forward thrust isrequired for vertical take-off, only sufficient jet velocity to provideyaw control by means of the jet rudders 28. When the rotor has been)brought up to speed, take-01f is effected by pulling backward on thelever 166 to increase the collective pitch, pitch and roll control beingeffected by the proper manipulation of the lever :102. If it is desiredto rise vertically, the lever 1102 may be pulled backward somewhat tocause the lift vector of the rotor to slant backward sufficiently toovercome the forward thrust of the turbo jet. When sufficient height hasbeen attained, a forward movement of the stick 102 will cause theaircraft to gain forward speed. As forward speed increases, less rotorpower is required to sustain the weight of the aircraft and the airvalve 52 may be moved toward the closed position. If fuel is beingburned at the rotor tip, a corresponding movement of the control 59 mayalso be effected. This will reduce the amount of air bled from the turbojet compressor so that more air will be avail-able to the turbo jet forforward thrust. This will permit an additional opening of the turbo jetthrottle without increasing the turbine intake temperature. Thus, theturbo jet forward thrust will increase rapidly as the air bled to therotor is reduced. It may be mentioned here that increasing the air bledfrom the turbo jet will necessitate reduction of the turbo jet fuelsupply if a predetermined turbine intake temperature is not to beexceeded. However, if conservative normal maximum temperature isemployed, this could of course be exceeded temporarily during a shortperiod of ta re-off. After takeoff the alighting gear may be retractedand if conversion to high speed fixed wing flight is desired, the turbojet throttle may be advanced and the collective pitch of the rotorprogressively reduced as the speed increases by advance of the lever166.

The angle of incidence of the fixed wing 29 must be suficiently positivethat, as the collective pitch of the rotor is reduced, the weight of theaircraft will be transferred from the rotor to the fixed wing. When theweight of the aircraft can be carried by the fixed wing 20, thecollective pitch lever 166 is positioned to bring blades 16 to the angleof zero lift and the plane of the rotor may be parallel to the flightdirection. The stick 102 may be in the neutral position so that there iszero cyclical pitch change of the rotor blades. As the rotor is mountedon its shaft by the flapping hinge pin 2%, the rotor shaft may beperpendicular to the flight direction to maintain the rotor at zeroangle of attack. The fixed wing should have a considerable angle ofattack to provide the total lift at near its minimum forward speed.There could therefore be an appropriate angular relation between therotor shaft and the fixed wing to transfer completely all the load tothe fixed wing and to leave the rotor in a zero lift conditionpreparatory to rotor contraction. It is also important that the angle ofthe fuselage, with relation to the angle of the fixed wing, should besuch as to produce minimum drag during high speed flight. If the rotorshaft is perpendicular to the major axis of the fuselage, then the fixedWing Zll must be given a substantial positive angle relative to themajor axis of the fuselage so that the fixed wing will support the totalweight with the plane of the rotor parallel to the flight directionprior to rotor contraction. In this case the fuselage would be tail highduring high speed flight. An alternative to this would be to mount thewing so that its angle relative to the fuselage may be varied, or it maybe mounted at a low angle with respect to the fuselage and depressibletrailing edge flaps provided to produce the high lift. An advantageousalternative is to mount the fixed wing at an angle to the fuselage equalto or slightly greater than the high speed angle of incidence and tomount the rotor shaft with a forward slope relative to the fuselage. Thealighting gear would then be arranged so that the fuselage rested taillow on the ground With the plane of the rotor parallel to the ground. Inthis case the fuselage and fixed wing would both be at a considerablepositive angle of incidence relative to the flight direction duringtransition. During hi h speed flight the fuselage and fixed wing wouldhave suitable low drag angles and the angle of the rotor shaft has noeffect at high speed because the rotor is retracted. This latterarrangement is advantageous as no variable wing incidence or flaps arerequired and suitable angle between the wings and fuselage at high speedare provided. The positive fuselage angle at the transition speed isquite acceptable. This arrangement is illustrated in FIGURE 23. Thechord of the fixed wing A may be mounted for instance at an angle offive degrees relative to the major axis of the fuselage B. The axis ofthe rotating wing C may be mounted at a forwardly slanted angle ofeightyfive degrees relative to B. Thus when the plane of the rotor isparallel to the flight direction the fuselage axis B has a five degreeangle and the wing chord A a ten degree angle relative to the flightdirection. During transition the stick 102 should be in neutral topermit proper engagement of the control sectors 2&0, 214, 216.Therefore, elevators may be provided with sufficiently powerful trimmingtabs 27 so that the wing 20 may be given for instance a ten degree angleof incidence to the flight direction with the stick 102 in neutral bymeans of trimmer control 29. It will also been seen from FIG- URE 23that during high speed flight when the rotating wing is retracted thefixed wing chord may have a two and one-half degree positive angle ofincidence relative to flight direction while the angle of the fuselageaxis B has a two and one-half degree negative angle thereto.

When the rotor is in its no lift condition, the rotor air valve 52 maybe completely closed and the jet drive of the rotor completely shut off.When the rotational speed of the rotor is reduced to the point Where thecentrifugal force, tending to maintain the blades 16 in their extendedposition, is sul'liciently reduced the electric motors 262 are startedin the proper direction to retract the blades 16 into the center section18. After the blades 16 have-moved inwardly until the flexible section282 and the rigid section beyond it are within the center section 13,the blades 16 disconnect from the blade pitch control by the unmeshingof the sectors 216 from the sectors 216 and 214. As the blades 16 areapproximately at the angle of zero lift, they are in position forretraction and they may be retracted without any change of angle. Afterthe disconnection of the blade pitch control, the stick 162 may bemanipulated as desired for pitch and roll control by means of theailerons 21 and elevators 25 while the blades 16 are held at zero pitchby their entry into the center section Due to the flapping pivot 239,the plane of the rotor will tend to follow the movements of the fuselagein response to the ailerons 21 and elevators 25 as the rotor will tendto remain perpendicular to its shaft 68. When no torque is exerted onthe blades either from the tip jets or from autorotation, they will tendto slow down and stop. However, the slowing will be retarded by theinward movement of the blade masses during contraction. The angulardeceleration may be increased by means of rotor brake 69 applied torotor shaft 63 or decreased by appropriate opening of rotor jet valve52. During or after contraction of blades 16 into the center section 18,the relative air flow over the inner part or all of the retreatingblades will reach zero or reversed velocity due to the aircrafts forwardspeed. However, as the rotor is operating at very small or zero lift,there is little or no problem of unequal lift on the advancing andretreating blades. Nevertheless, it may be desirable that the blades 16be completely or nearly completely contracted within the center sectionbefore the tip speed becomes less than the forward speed of theaircraft, that is before the advance ratio exceeds unity. This wouldprevent any great reversal of flow except over the center section whichis symmetrical, fore and aft, chordwise and very rigid. The bladesection may also be symmetrical chordwisc. On the other hand, the speedof the blade at the start of and during contraction should not be morethan necessary to maintain adequate blade stability so that contractionmotors 262 may overcome the centrifugal forces without being ofexcessive bulk. When the blades 16 have been completely contractedwithin the center section 18, the motors 262 are stopped either manuallyor automatically and the center section 18 is brought to a full stopwith its major axis parallel to the major axis of the fuselage by propermanipulation of the rotor brake 69, the rotor air supply valve 52, orboth. After the blades 16 are completely contracted into the centersection 18, the rotor is relatively compact and has much greaterrigidity than when extended. The electric motor may now be started inthe proper direction to lower the elevator member 76 by means of thescrews 78 to retract the contracted rotor 14 into the depression 12 inthe top of the fuselage. In this position it fills the depression 12 andforms a smooth continuation of the top surface of the fuselage, as shownin full lines in FEGURES 1, 2 and 3. The aircraft now has the smoothstreamlined exterior of a high speed fixed wing jet aircraft and mayproceed to carry out its mission as such.

If it is not intended for operation at very high altitudes, the fixedwing 20 may be smaller than would be required if landing and take-offwere not effected by means of the rotating wing. It may be pointed outthat little, if any, drag is added to the aircraft by the rotating wingwhen retracted. The main price paid for the great advantages of therotating wing is the added weight which this entails. However, this maybe offset by a reduction of weight due to a smaller fixed wing withoutflaps and a much lighter landing gear than is required for high speedlanding and take-01f. Even very low retractible skids, not shown, mightbe employed for this purpose instead of wheels. It will also be seenthat no extra power plant, compressor, reduction gearing or countertorque device is required for the rotor drive and that the large turbojet power plant required for flight at high Mach numbers supplies a veryample source of rotor power at low speed when little forward jet thrustis required. The pressure jet rotor drive provided, while consumingconsiderable fuel, need only be operated for short periods. A furtheraid to the reduction of drag is the retraction of the contractedrotating wing behind the pilots cockpit, which avoids adding anyprojected area for the retracted rotating wing at the top of thefuselage. Thus, high speed and the ability to hover motionless issupplied in a single aircraft with minimum added weight and little or noadded drag by comparison even to a turbo jet figher aircraft.

When the aircraft arrives at its destination flying as a fixed wingturbo jet aircraft, conversion from fixed wing to rotating wing flightfor landing may be effected by folthe full load stailling point of thefixed wing 2%.

1 7 lowing a procedure generally the reverse of that described inconverting from rotating wing to fixed wing flight. The electric motor90 is started in the proper direction to raise the rotor 14 to itsuppermost position where the rotor may be extended to its maximumdiameter and may flap around the flapping bearings 194, 2% without thetips of the blades 16 striking the top of the fuselage or the tail. Itshould be noted however that before this is done the speed of theaircraft should be reduced to near the minimum safe speed for fixed wingflight. After the rotor 18 is elevated, it is put into rotation by meansof opening the rotor air valve 52. If the tip burners are to beoperated, these may be started when the blades 16 are considerablyextended. The extension of the blades is accomplished by starting themotor 262 in the proper direction to extend the blades 16 outward fromthe center sec tion 18. It may be noted that when the blades are beingexpanded, the centrifugal force aids the motors 262 in effecting theexpansion and it is therefore not necessary to keep the speed of therotor low during expansion to avoid excessive load on the motors as maybe the case during contraction and it may be desirable to increase thespeed of the rotor before extension is started so as to eliminate orreduce reverse air flow over the retreating blade during expansion. Whenthe blades near the end of their outward travel, the controls 102 and166 should pands, more power must be supplied to increase its rotationalspeed by appropriate opening of the valve 52 and the valve 57 when andthe tip burners are employed.

After the rotor is fully expanded and up to speed, the collective pitchcontrol is increased and the Weight of the aircraft is graduallytransferred from the fixed wing to the rotating wing. If rotating wingflight is to be continued for some time, part of the weight may becarried by the fixed wing but considerable weight should be transferredto the rotor by pulling backward on lever 166 before the forward speedof the aircraft is reduced below Prior to landing the turbo jet forwardthrust will be considerably reduced by the air bleed to the rotor jetsbut speed can be reduced to zero by suflicient backward movement of thestick 102 in spite of any jet thrust remaining. It will be understoodthat during rotor flight, pitch and roll are controlled by the lever W2and yaw by the foot pedals operating the jet rudders 28 Working inconjunction with the rudders 26. The same motion of the same controlsalso perform the similar functions during fixed wing flight. Prior tolanding, the landing gear is extended and the aircraft is lowered ontothe ground by appropriate operatron of the lever 16!; and propermanipulation of the turbo jet fuel control throttle. After landing therotor may be contracted and retracted if desired in a manner similar tothat previously described.

In the event that the turbo jet power plant should fail during fixedwing flight, the extension rotation and expansion of the rotating wingmay have to be effected without tip jet drive normally employed to startrotation of the rotor. A source of electric power may be provided forthe extension motor 90 and the expansion motors 262. An additional motor71 may be employed, operated from the same electric power sourceconnectable to the rotor shaft 68 by means of a disengageable geardrive, not shown, which may be similar to an automobile starter drive.As soon as the rotor is extended by the motor 99, the starting motor 71may be energized to start the rotor turning. The elevator 25 should beraised by a backward movement of the stick 102 enough to start and tomaintain autorotation. Then the blades may be expanded by means of theappropriate rotation of the motors 262. The motor 71 may automaticallydisengage itself from the rotor shaft 68 when the rotor becomes airdriven. When the rotor is completely expanded, the pitch of the blades16 are controllable by the stick 162 and collective pitch lever 166 anda normal autorotational power off landing can be made, as in theconventional helicopter or autogyro.

It will be seen that changes from one flight regime to another may beeffected gradually and with the minimum possibility of instabilityduring transition. The stability of the rotor during expansion andcontraction is effected by relieving the rotor of all or nearly alllift, maintaining zero or no lift angle of incidence of its blades, andzero or no lift angle of the rotor disc to the flight direction. It isalso desirable to maintain sufilcient rotative speed to avoid orminimize reversal of the flow over the blades 16, at least near thetips, until they are completely or considerably contracted within thecenter section 14. The main limitation on the employment of thisprocedure is overcoming the centrifugal force of the blades while inrapid rotation during contraction. This may require compromise betweenthe rotative speed desired and the forces which may be practicallyprovided for retraction by motors 262.

FIGS. 15, 16 and 17 illustrate a modified rotating wing which is notadapted for contraction to a reduced diameter but which may employ ablade construction similar to that shown in FIGS. 11, 12, 13, and 14 andwhich also may be driven by rotor tip jets supplied with fluid by meanssimilar to those shown for instance in FIGS. 2 and 4. The aircraft whichcarries this non-retractible rotor may be regarded as similar to theaircraft of the previously described embodiment when its rotor isextended immediately prior to retraction for high speed fixed wingflight. In other words, the high speed flight of the nonretractiblerotor aircraft is similar to the transitional flight condition of theretractible rotor aircraft. The pitch change mechanism below the hub ofthe non-retractible rotor may also be similar to that of the previouslydescribed embodiment. Closely similar parts in this and the precedingembodiment are indicated by similar numbers.

A flexible section 282 connects the hub casing 332 to the blade 16. Thecasing 332 is mounted on the hub flange structure 334. The housings 22Sand 236 for the bearings 22% and 222 are carried on the hub flangestructure 334. The blade root member 218 may be secured at its outer endto the blade 16 as described in the previous embodiment and its innerend may be mounted in the bearings 220 and 222 for pitch change aspreviously described.

The sector 216 on the blade root member may mesh permanently with thesector 21% on the pitch change shaft 208. This shaft is held in bearings336 and 337. Fixed to the inner end of the shaft 208 are pitch changelevers 206. These connect to control rods 138, and the pitch changemechanism may be as previously described and as described in AndrewsPatent No. 2,511,687. The hub flange 334 is secured to the shaft 68through flapping bearings 194, 198, pin 2% and yoke 1% as previouslydescribed. The hub flange 334 is sealed to the rotating element of thesealing chamber as previously described and shown, and the seal betweenthe rotating member of the sealing member 66 and the stationary memberof the sealing chamber 65 is similar.

As the non-contractible rotor of this embodiment is adapted for anaircraft having a lower top speed than that shown in the previousembodiment, a smaller turbo compressor for an aircraft of similar weightmay be employed. Because of the lower top speed the forward jet thrustmay be augmented by a ducted fan or small diameter high speed propellerdriven by a separate stage of the turbo compressor, as shown in FIG. 2a.A large propeller is unnecessary as take-off is effected by the rotorand requires little or no forward thrust. As in the previous embodiment,the rotor may be driven by fluid The aircraft on which the rotating wingof FIGURES 15, 16 and 17 is mounted may be somewhat similar to FIGURES1, 2 and 3 without rotor retraction and may be without the sweptbacl;wings. The fuselage may be considerably shortened from the front due tothe nonretractible rotor. When the rotor is employed for hoveringflight, the air bleed from the turbo compressor to the rotor will takemost of the power and the separate turbine stage driving the propulsivefan will slow down and deliver only small forward thrust. The power fromthe common turbo power source may also be cut oil. from the rotor andtransferred to the propulsive or ducted fan by closing the valve 52 andmaking proper turbo jet throttle adjustments. The rotor and fixed wingcontrols may be linked as previously shown but without the provisionsrequired for rotor retraction and extension. The axis of the rotor maybe substantially perpendicular to the major axis of the fuselage asshown and the chord of the fixed wing may have a moderate angle relativeto the fuselage so that this angle is that required for high speed orcruising flight with the axis of the fuselage generally parallel to theflight direction. At top speed the weight of the aircraft is carriedmainly by the fixed wing and the rotor is unloaded for maximum reductionof drag. The rotor control linkage may be unmeshed and the rotor bladeslocked in zero lift position and the plane of the rotor maintainedperpendicular to the rotor shaft by the action of the flapping hinge aspreviously described.

The non-retractible rotor aircraft may carry little or no weight on therotor during high speed flight, in which case the rotor must receivesufficient power to maintain a speed of rotation which will providesufiicient rotor stability. This may be effected by small discharge offluid from the tip jets or the rotor may be adjusted to supply theminimum lift required to maintain autorotation. The function of therotor is to supply lift during hovering and low speed flight. At highspeed its stability should be preserved and its drag minimized. As therotor may provide little or no lift or forward thrust, high speed is notlimited by retreating blades stall. The effect of compressibility on theadvancing blade may also be largely eliminated by slowing the rotationalspeed at high forward speed to the minimum angular speed at whichstability can be maintained. It may be noted here that in the case of acontractible rotor of a previous embodiment such slowing of the rotorbefore contraction may be advantageous in that the centrifugal forcesopposing contraction are reduced.

FIG. 18 shows a modified means of contracting the blades 16 into andextending them out of the center section 18. In this modification themotors 262 shown in FIG. are not employed. Instead, a motor 338 ispermanently located at each end of the center section 18. The motor 333drives the drum 340 through the reduction gear 342; the pulley 272 issimilar to that shown in FIG. 10 but the drum 340 replaces the forwardpulley of this pair. Several turns of the cable 268 are wrapped aroundthe drum 340 so that the cable is powerfully driven from the drum. Thismakes unnecessary the rack 248, gears 252, cross shaft 242, worm wheel254, Worm S, worm wheel 260, the motor 262, and worm 264, shown in FIG.10. The motors 333 would be operated to extend and retract the blades inthe same way as described in the first embodiment except that it wouldbe unnecessary to provide the rails and brushes required for the motors262 as the motor 338 is fixed at the ends of the center section and doesnot travel from one end of the center section to the other as do themotors 262. However, the cable 268 in FIG. 16 must be capable ofwithstanding greater loads than that shown in FIG. 10 because in theembodiment of FIG. 10 the cable only acts as an equalizer, while in theembodiment of FIG. 18 it carries the full load of the retraction andextension force. Where this embodiment is employed it may be necessaryto slow this rotor to a lower rotational speed before rotor bladecontraction. 7

FIG. 19 illustrates an attachment of the rotor of the rotating wing 14-to the shaft 68 which permits pltch change by changing the angle of thecenter section around an axis 344 perpendicular to the flapping axis. Inthis embodiment the yoke 346 is connected by flapping bearings 34-3 to agimbal member 350. This gimbal member is in turn pivotally mounted tothe center sect on flange '72 by the bearings 352 and the pin 354 whichestablish the axis 344. By changing the angle of the center sectionaround the axis 344, cyclical or different al pitch change may besecured without changing the angle of the blades 16 relative to thecenter section 18. The angle change between the blades 16 and the centersection 13 may in this embodiment be employed solely for collectivepitch change. This ma'y be elfected by operating the motor 356 in onedirection to reduce collective pitch and in the opposite direction toncrease it. Similar parts are given the same numbers n FIG. 19 as inprevious embodiments, and the operation of corresponding parts are thesame as previously described. The cyclical pitch is changed by rod 358and pivoted lcvcr 366 which connects to control rod 358. Rod 358 isoperated cyclically from the wabble plate 148. The collective pitchchange mechanism shown in Andrews Patent No. 2,511,687 would not berequired here as the c ollective pitch is changed by the motor 356, aspreviously described. The center section 14 and the supply of fluidunder pressure from the compressor 51) through the sealing chamber tothe center section and thence to the tip jets may be the same or similarto that shown and de scribed in previous embodiments. q

The motor 356 may be stopped or operated in either direction by means oftriple conductor cable 362 which may be carried into the fuselagethrough slip rings as previously described, and may be controlled by athreeposition reversing switch operated by the collective pitch changelever 166 which would then not require any connection with the pitchchange mechanism described in previous embodiments.

FIGS. 20, 21, and 22 illustrate a further embodiment in which the blades16 are in the same plane instead of being one above the other and inwhich the blades are less than half as long as the center section and donot contract beyond the center of the center section. The same numbersare employed to designate corresponding parts as in previousembodiments. I

FIG. 20 shows the carriages 192 contracted in their innermost positionfor maximum contraction of the blades 16 into the center section 18.FIG. 21 shows the blades 16 extended to the maximum with the carriage192 0c copying a position adjacent the outer end of the center section18. The carriages 192 may be operated for expansion and contraction ofthe blade in a manner similar to that described in previous embodiments.The motors 262 as shown may be replaced by the motors 338, if de sired.The blades 16 may be mounted in the carriages 192 for pitch change inthe same manner as previously described. FIG. 22 is an end view of theblades 16 and the center section 18. It will be seen that the carriagesupport plate 364 in this embodiment is located at the lower portion ofthe center section and that the carriages 192 for both blades aremounted above the carriage support plate 364- instead of one above andone below, as

in the previous embodiments. This provides a thinner center section;however, the center section must have a considerably larger diameter forthe same expanded diameter of rotating Wing as compared with embodimentof FIGS. 8 and 10. However, the operation of expansion and contraction,pitch change, and the supply of rotor propulsive fluid to the rotor fromthe compressor may be substantially the same as in previous embodiments.This also applies to the construction of the blades including theconstruction of the tips to supply the propulsive jets. It may bepointed out that in this embodiment the flapping hinge may be in theplane of the blades 16 if desired as both blades 16 are in the sameplane and no part of the blades contract past center. The universaljoint of FIG. 19 might also be mounted in the same position instead ofthe single flapping hinge.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is as follows:

1. In a convertible aircraft having a main structure including a fixedwing adapted for high speed flight, a lifting rotor mounted for rotationon said structure, a turbo compressor comprising a turbine rotor,compressor means driven by said turbine rotor, a separate turbine rotor,a ducted fan directly driven by said separate turbine rotor adapted forhigh speed horizontal propulsion, air jet means on said rotor suppliedwith compressed air from said compressor means for rotating said rotorto supply substantially all lift during low speed flight, valve meansfor diverting the flow of compressed air from said rotor jet means tothe production of large horizontal thrust from said turbine exhaust andsaid ducted fan during high speed flight with the weight of the aircraftsupported mainly by said fixed wing, means on said rotor for controllingits collective pitch, means operatively connected to said fixed wing foradjusting the angle of attack of said fixed win g to sustain more orless of the aircrafts weight and manually operated control means forreducing the collective pitch of said rotor and adjusting the effectiveangle of attack of said fixed wing as the valve means is operated todivert the flow of compressed air from the rotor jet means to theproduct-ion of large horizontal thrust from said turbine exhaust andsaid ducted fan.

2. A convertible aircraft having a fusela e, a fixed wing mountedthereon adapted to carry the weight of the aircraft at high speed withthe major axis of the fuselage substantially aligned with the flightdirection and with said major fuselage axis inclined to the flightdirection at lower speed, a two-bladed lifting rotor mounted forrotation on said fuselage, a recess in said fuselage extending along themajor axis thereof adapted to receive said blades, turbine means,turbine combustion chamber means and air compressor means in saidfuselage, a rotor combustion chamber adjacent each blade rtip suppliedwith fuel and mixed with compressed air from said compressor means,nozzle means discharging combustion products rearwardly from saidcombustion chambers for rotor rotation supplying substantially all liftat lowest flight speed, valve means for stopping the supply of fuel tosaid rotor combustion chambers, valve means to cut off the compressedair supply to said rotor combustion chambers and to divert said airsupply to the production of horizontal thrust, collective pitch controlfor said rotor, elevator means carried by said fuselage for adjustingthe angle of attack of said fixed wing relative to the flight direction,manually-operated control means for reducing the collective pitch ofsaid rotor and increasing the effective angle of attack of said fixedwing relative to the flight direction as the valve means are operated todivert the flow of compressed air and fuel from said rotor bladecombustion chambers to the turbine combustion chambers for horizontalthrust, means for stopping said rotor with itstwo blades in alignmentwith said recess and retracting them to a low drag position thereinwhereby the aircraft is converted from low speed flight sustained by thelifting rotor to high speed flight with the rotor in retracted low dragposition and the weight sustained by the fixed wing with the major axisof the fuselage generally aligned with the flight direction.

3. In a convertible aircraft having a fuselage, a fixed wing mountedthereon, a lifting rotor mounted for rotation on said fuselage, a turbocompressor power means in said fuselage, rotor combustion chamber meanson said rotor supplied with air under pressure from the compressor meansof said turbo compressor power means, rotor fuel supply means and rotorjet discharge means from said rotor combustion chamber means to rotatesaid rotor supplying substantially all lift during low speed flight,means for stopping the fiow of air and fuel to said rotor combustionchamber means and providing large horizontal thrust from said turbocompressor exhaust and said compressor means during high speed flight,means on said rotor for controlling the collective pitch thereof, meansoperatively connected to said fixed wing for controlling the angle ofattack of the fixed wing and manually-operated control means forreducing the collective pitch of said rotor, adjusting the angle ofattack of said fixed wing and for operating said air flow stopping meansfor transition from low speed to high speed flight.

4. In a convertible aircraft having a main structure including a fixedwing, a lifting rotor mounted for rotation on said structure, turbo-jetpower means including an air compressor, a combustion chamber, acompressor turbine connected to said combustion chamber and driving saidair compressor, a separate turbine connected to receive the gasdischarge from said compressor turbine, a ducted fan driven by saidseparate turbine, the output of said ducted fan discharging at the rearof the fuselage together with the exhaust of said compressor turbine,propulsive jet means on said rotor supplied with ai1 under pressure fromsaid air compressor for rotating said rotor to supply substantially alllift during low speed flight, means for stopping the fiow of compressedair to said rotor propulsive jets and diverting it to the compressorturbine and separate turbine to provide large horizontal thrust fromsaid compressor turbine exhaust and said ducted fan during high speedflight, means on said rotor for decreasing its collective pitch andreducing its lift, means operatively connected to said fixed wing forincreasing its angle of attack to transfer lift from said lifting rotorto said fixed wing and manually operated control means for reducing thecollective pitch of said rotor and first increasing the angle of attackof said fixed wing as the air flow to said rotor propulsive jet is cutoff and then decreasing said angle of attack as the horizontal thrust ofsaid exhaust and said ducted fan increases the forward speed of saidaircraft.

5. A convertible aircraft having a fuselage, a fixed Wing adapted forhigh speed flight associated therewith, a two-bladed lifting rotormounted for rotation on said fuseleage, a recess along the major axis ofsaid fuselage adapted to receive said rotor blades, means associatedwith said rotor to retract said blades into said recess and extend themtherefrom for rotation, turbine power means, air compressor means andcombustion chamber means in said fuselage, propulsive jet means on saidrotor supplied with compressed air from said compressor means forrotating said rotor to supply substantially all lift during low speedflight, valve means for diverting the flow of compressed air from saidrotor jet means to the production of large horizontal thrust by saidturbine power and compressor means, means for bringing said rotor to astop with the two blades substantially in alignment with said recess andretracting them to low drag position therein, means on said rotor forcon trolling its collective pitch, elevator means operatively connectedto said fixed wing for adjusting its angle of attack to sustain more orless all of the aircrafts weight, manually operated control means forreducing the collective pitch of said rotor and adjusting the angle ofattack of said fixed wing as said valve means is operated to divert theflow of compressed air from said rotor jet means to the production oflarge horizontal thrust, control means for stopping and retracting saidrotor after the angle of attack of said fixed wing has been adjusted tosupport the weight of the aircraft, whereby the aircraft is convertedfrom low speed flight sustained by the lifting rotor to intermediatespeed flight with the fixed wing supporting the weight and then to highspeed

3. IN A CONVERTIBLE AIRCRAFT HAVING A FUSELAGE, A FIXED WING MOUNTEDTHEREON, A LIFTING ROTOR MOUNTED FOR ROTATION ON SAID FUSELAGE, A TURBOCOMPRESSOR POWER MEANS IN SAID FUSELAGE, ROTOR COMBUSTION CHAMBER MEANSON SAID ROTOR SUPPLIED WITH AIR UNDER PRESSURE FROM THE COMPRESSOR MEANSOF SAID TURBO COMPRESSOR POWER MEANS ROTOR FUEL SUPPLY MEANS AND ROTORJET DISCHARGE MEANS FROM SAID ROTOR COMBUSTION CHAMBER MEANS TO ROTATESAID ROTOR SUPPLYING SUBSTANTIALLY ALL LIFT DURING LOW SPEED FLIGHT,MEANS FOR STOPPING THE FLOW OF AIR AND FUEL TO SAID ROTOR COMBUSTIONCHAMBER MEANS AND PROVIDING LARGE HORIZONTAL THRUST FROM SAID TURBOCOMPRESSOR EXHAUST AND SAID COMPRESSOR MEANS DURING HIGH SPEED FLIGHT,MEANS ON SAID ROTOR FOR CONTROLLING THE COLLECTIVE PITCH THEREOF, MEANSOPERATIVELY CONNECTED TO SAID FIXED WING FOR CONTROLLING THE ANGLE OFATTACK OF THE FIXED WING AND MANUALLY-OPERATED CONTROL MEANS FORREDUCING THE COLLECTIVE PITCH OF SAID ROTOR, ADJUSTING THE ANGLE OFATTACK OF SAID FIXED WING AND FOR OPERATING SAID AIR FLOW STOPPING MEANSFOR TRANSITION FROM LOW SPEED TO HIGH SPEED FLIGHT.